JSFiddle - React, Tailwind, and code Playground

HTML

<div ></div>

JavaScript

var sourceObj = {
    propterty:"change Me",
    anArray:[
        {name:"first"},
        {name:"second"}
    ]},
    configJSON = '{"propterty":"New Val","anArray":[{"name":"third"}]}',
        x = JSON.parse(configJSON);
// before
$("div").append(JSON.stringify(sourceObj)) 
    
$.extend(true,sourceObj,x);
//after
$("div").append("<br>"+JSON.stringify(sourceObj))